Check Common Wifi Connectivity
The Fundamentals of Internet Protocol Addressing
When connecting to the Internet, you are assigned a unique Public IPv4 address, such as 137.245.166.170, or an IPv6 address like 2000:e48c:7e5c:354b:30da:2fa4:4a87:176c. You can verify this by visiting https://test-ipv6.com/. However, explaining or communicating these addresses, or even mentioning unique MAC addresses like e1:5e:0d:bf:6a:8c, can be prone to errors and quickly becomes complicated, especially for those unfamiliar with technical jargon. Moreover, this information does not provide any historical context, especially when dealing with past issues.
Navigating the Web
When attempting to access a website such as https://beer.name, the initial step involves contacting a DNS server to translate the combined host (beer) and Top Level Domain (name) of the URL into an IP address, such as 120.185.222.9. Your computer and browser send their specifications along with all web requests, for instance: Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0.
Understanding the Significance of Default Gateways
By default, your computer is assigned a gateway address through DHCP, typically like 192.168.11.175 (although they often end in .1 or .254 depending on the scope size). This gateway is responsible for routing all of your computer’s traffic to its intended destinations. For IPv6, detailed instructions are provided in our blog post how-to-fix-ipv6-connectivity/, and you can perform checks on Mac or Linux using:
IPv4 Routes and the Host IPv4 Route Table (inc. VPN)
netstat -rn -f inet | egrep -i "default|0/1|128.0/1"
0/1 172.18.12.193 UGScg utun3 default 192.168.11.175 UGScg en0 128.0/1 172.18.12.193 UGSc utun3
Note: We are not just looking for the default but also for any VPN that overrides the public v4 address space.
IPv6 Routes and the Host IPv6 Route Table (inc. VPN)
netstat -rn -f inet6 | egrep -i "default|2000::/3"
If you have IPv6 active the above should return at least one route (as per below) via a known interface such as “en0 " on a Mac.
default fe80:fbf7:9306:d03a:20f8%en0 UGcg en0 default fe80::%utun0 UGcIg utun0 default fe80::%utun1 UGcIg utun1 default fe80::%utun2 UGcIg utun2 2000::/3 utun3 USc utun3
Note: We are not just looking for the default but also for any VPN that overrides the public v6 address space.
Debugging DHCP for both IPv4 and IPv6
To get a look at the low level DHCP configuration (Mac/Linux):
ipconfig getpacket en0
...
domain_name_server (ip_mult): {42.201.195.168, 63.229.90.6}
end (none):
...
So, in the above we are not getting IPv6 DNS servers from the DHCPv4 reply but…
ipconfig getv6packet en0
DHCPv6 REPLY (7) Transaction ID 0x80940b Length 76
Options[4] = {
CLIENTID (1) Length 14: DUID LLT HW 1 Time 668691856 Addr e1:5e:0d:bf:6a:8c
DNS_SERVERS (23) Length 32: 2606:4700:4700::1111, 2001:4860:4860::8844
DOMAIN_LIST (24) Length 0: Invalid
SERVERID (2) Length 10: DUID LL HW 1 Addr 36:6e:ec:3d:03:1b
}
Fixing Issues with Wired and Wireless Connections
When it comes to sending data to your router, you may be using either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Tips for Apple macOS / OSX
Regardless of whether you’re using OSX/macOS 10.15.9, 11.3.9, or 12.0.7, there are various tools available for troubleshooting. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting shines, especially for teams that practice remote work and Work From Anywhere (WFA).
Utilizing Built-in Scripts for Help
A very useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump of current wireless settings to the CLI and can also generate specific logs for troubleshooting purposes. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although many of them are only relevant to wireless settings, similar to wdutil.
To run the command in the background and write logs to /var/tmp/<blah>.tar.gz, use sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, you can use sudo /usr/bin/sysdiagnose, which will give a privacy warning. When not run in the background, it should open Finder in the correct location, or you can navigate to /var/tmp using Finder with Cmd+Shift+G. Keep in mind that the file sizes are around 300MB more or less.
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Digital work requires reliable connectivity. Whether for low latency or regular data streams, Wi-Fi, DNS, and network issues cause teams to lose time and productivity. Even worse is when support teams waste time trying to recreate and isolate issues! See how PanSift saves time, money, and frustration on all sides with instant remote troubleshooting 🏠🏝🛰.
